Indicator signs, such as exit signs and the like, are mandated by legislation to be mounted in strategic locations in commercial buildings. Such indicator signs are used to indicate the location of an adjacent building exit, the hallways leading to such exits, and so on. These indicator signs are typically mounted either on the walls that define the hallways or rooms, or the ceiling overhead. In the event of a fire or other emergency, indicator signs often play a life-saving role in assisting people to quickly navigate the hallways of a building and exit the building safely.
Most prior art indicator signs are illuminated to be visible in the dark by way of light emitting diode (LED) type lights mounted within the sign. The light emitting diode (LED) powered signs would of course be illuminated only while electrical power is available, either from a conventional hydro-electric source or from a back-up power system, either generator or battery. However, these types of signs cannot illuminate when no electrical power is available, which might happen during extreme and/or unusual conditions. The resulting non-illuminated indicator signs could be very unsafe in this situation.
In response to this potentially unsafe situation, some prior art indicator signs uses photo-luminescent material without light emitting diode (LED) type lights, as a source of illumination.
United States Published Patent Application No. 2010/0018092, published Jan. 28, 2010, to Peckham, and entitled, discloses a Photo-luminescent Exit Signs And Methods For Forming Same. The photo-luminescent sign includes a generally planar faceplate comprising a plurality of openings defining various characters. At least some of the periphery of the openings comprises an angle relative to the surface of the faceplate. A backplate has a photo-luminescent material and is disposed adjacent to the faceplate so as to result in the illuminated letters defining the various characters.
WIPO Published Patent Application No. WO2009/025566, published Feb. 26, 2009, to Rotarski, and entitled Photo-Luminescent Visual Information Sign, discloses a photo-luminescent visual information sign comprising a transparent plate with a photo-luminescent layer applied on one face. The photo-luminescent layer has the required indicators. The transparent plate with a photo-luminescent layer are secured with a cover of removable protective foil. The opposite face of the transparent plate has a colored layer that is the background for the image. A foam foil having adhesive on both sides is also applied to the same face of the transparent plate as the colored layer, for mounting the sign.
The disadvantage of these types of indicator sign is that it must be placed near a significant source of illumination in order to retransmit sufficient light to be acceptable.
Also in response to this potentially unsafe situation, some prior art indicator signs that are usually lit by light emitting diode (LED) type lights, also illuminate when no electrical power is available. Typically, this is accomplished by additionally employing a photo-luminescent material in some capacity in conjunction with light emitting diodes (LEDs) to light, to provide a hybrid light source. Various ones of these hybrid light source indicator signs will now be discussed, along with their various disadvantages.
United States Published Patent Application No. 2006/0291187, published Dec. 28, 2006, to Huang, and entitled Illuminated Sign, discloses an illuminated sign that stores light energy and emits light spontaneously, via a photo-luminescent and marking layer that absorbs light, to make an icon on the photo-luminescent and marking layer visible. The light is generated from a light emitting module that couples to a power supply module for getting power. The photo-luminescent and marking layer is disposed on an opaque substrate. Moreover, the device can also emit light by a photo-luminescent layer that receives light from the light emitting module and stores the light energy so as to illuminate the icon on a marking layer over the photo-luminescent and marking layer. Problems with this design include the following. The photo-luminescent and marking layer is small compared to the overall size of the sign. Accordingly, only a fraction of the light energy shining on the sign from the light emitting diodes (LEDs) is actually absorbed by the photo-luminescent material.
United States Published Patent Application No. 2013/0199064, published Aug. 8, 2013, to Okell, and entitled Signs, discloses a sign having a sign plate mounted in a frame to display an image when illuminated. The sign includes an electrically powered light source configured for edge lighting of the sign. The sign plate has a front portion, a rear portion and an intermediate portion between the front and rear portions. The rear portion provides a photo-luminescent light source for back lighting the sign. The sign is edge lit when the electrically powered light source is in use and is backlit by the photo-luminescent light source in darkness or low ambient light conditions when the electrically powered light source is not in use. Problems with this design include the following. The light-passing front portion is not configured to maximize the amount of light transmitted from the light emitting diodes (LEDs) and through the light-passing front portion and out of the front surface thereof. Further, it appears that the intermediate portion may reflect light, in which case the photo-luminescent rear portion has no apparent effect, or the intermediate portion may pass light, in which case there is no significant reflection of light emitted from the back side of the front portion.
U.S. Pat. No. 6,843,010, issued Jan. 18, 2005, to Robinson et al, and entitled Sign With Photo-Luminescent And Current-Generated Lighting, discloses a sign having a light-conductive and transparent front panel mounted in a frame. Etched characters are formed on a rear surface of the front panel, and photo-luminescent characters are disposed in overlying relation to the etched character. A strip of light emitting diodes (LED's) is mounted in the frame adjacent to a side wall of the front panel. Mounting members are formed on the frame to position and hold the front panel in place. Problems with this design include the following. The light-passing front panel is not configured to maximize the amount of light transmitted from the light emitting diodes (LEDs) and through the light-passing front panel and out of the front surface thereof. Further, the light-passing front panel is not configured to maximize the amount of light transmitted from the light emitting diodes (LEDs) to the photo-luminescent material. Also, the photo-luminescent indicators are small compared to the overall size of the sign. Accordingly, only a fraction of the light energy shining on the sign from the light emitting diodes (LEDs) is actually absorbed by the photo-luminescent material. Further, the indicators cannot readily be changed.
United States Published Patent Application No. 2012/0102799, published May 3, 2012, to Roberts et al., and United States Published Patent Application No. 2012/0227296, published Sep. 13, 2012, to Roberts et al., and United States Published Patent Application No. 2015/0007468, published Jan. 8, 2015, to Roberts et al., each entitled Current-Generated Photo-Luminescent Hybrid Sign, disclose a sign having a peripheral frame that retains a rear plate and a dual front plate comprising an inner cover plate and an outer cover plate. A large internal space separates the rear plate and the inner cover plate. The outer cover plate has a character aperture and characters of a photo-luminescent material are secured to the outer surface of the inner cover plate. An LED strip is disposed at the bottom of the interior of the sign provide illumination when the power is on. Problems with this design include the following. The light-passing inner cover plate is not configured to maximize the amount of light transmitted from the light emitting diodes (LEDs) and through the light-passing front panel and out of the front surface thereof. Further, the light-passing inner cover plate is not configured to maximize the amount of light transmitted from the light emitting diodes (LEDs) to the photo-luminescent material. Further, the indicators cannot readily be changed.
United States Published Patent Application No. 2004/0244247, published Dec. 9, 2004, to Bolta, and entitled Photo-Luminescent And Light Source Combination Exit Sign, discloses a sign comprising a photo-luminescent material and at least one light source adjacent the photo-luminescent material for charging the photo-luminescent material. Problems with this design include the following. The light emitting diodes (LEDs) and the photo-luminescent material are not positioned to maximize the amount of light transmitted from the light emitting diodes (LEDs) to the photo-luminescent material. Also, the photo-luminescent and marking layer is small compared to the overall size of the sign. Further, the indicators cannot readily be changed.
United States Published Patent Application No. 2013/0291413, published Nov. 7, 2013, to Lifka et al, discloses a light collector comprising a luminescent material element and a discontinuous semi-transparent layer adjacent to a first side of the luminescent material element. Due to the discontinuity of the semi-transparent layer, at least one first portion of the luminescent material element covered by the semi-transparent layer and at least one second portion of the luminescent material element not covered by the semi-transparent layer are formed. A light generating means is arranged at a second side of the luminescent material element. Further, a method for concentrating light in a light collector is provided, comprising the following method steps: capturing light from the environment by means of a luminescent material, concentrating the light in the luminescent material by means of a semi-transparent layer arranged on the luminescent material and light generating means, emitting the light in a pre-determined area of the light collector by means of an out-coupling structure so as to generate a pre-determined light emitting image.
U.S. Pat. No. 8,539,702 issued Sep. 24, 2013, to Li et al, discloses a light source comprising a blue emitting LED operable to generate blue excitation light and a light emitting surface comprising a light transmissive substrate and a phosphor. The LED is configured to irradiate the light emitting surface with excitation light such that the phosphor emits light of a second wavelength. Light emitted by the source comprises a combination of blue light from the LED and the second wavelength light from the phosphor. The light emitting surface is interchangeable thereby enabling the source to generate different selected colors of light using the same LED. The phosphor can be provided as a layer on the substrate or incorporated within the light transmissive substrate. The light emitting surface can be configured as a waveguide or as a light transmissive window.
United States Published Patent Application No. 2012/0227296 published Sep. 13, 2012, to Roberts et al, discloses a current-generated photo-luminescent hybrid sign that includes one or more light emitting elements within a channel in the frame to evenly distribute light, while concurrently energizing a photo-luminescent material in case of power outage. A hybrid current-generated photo-luminescent sign generally includes a frame, a front face plate, a rear plate, a mounting bracket, a light source and a power converter. The light source is disposed within a channel structure defined by the frame. The light from the light source shines upwardly to energize indicator characters in case of a power outage.
It has also been found, through experimentation, that it is difficult to get the photo-luminescent material to glow evenly, or in other words to emit a reasonably constant level of light across its entire surface, due to the placement of the light emitting diodes (LEDs) with respect to the photo-luminescent material. It is believed that at least most of the electrically powered prior art signs discussed above would have this problem.
It is an object of the present invention to provide a hybrid illuminated indicator sign for visually displaying indicators when the hybrid illuminated indicator sign is electrically powered and for at least a period of time when the hybrid illuminated indicator sign is no longer electrically powered.
It is another object of the present invention to provide a hybrid illuminated indicator sign for visually displaying indicators when the hybrid illuminated indicator sign is electrically powered and for at least a period of time when the hybrid illuminated indicator sign is no longer electrically powered, wherein The hybrid illuminated indicator sign emits at least a threshold amount of illumination for at least a threshold period of time when The hybrid illuminated indicator sign loses electrical power.
It is another object of the present invention to provide a hybrid illuminated indicator sign for visually displaying indicators when the hybrid illuminated indicator sign is electrically powered and for at least a period of time when the hybrid illuminated indicator sign is no longer electrically powered, wherein the indicators of The hybrid illuminated indicator sign are viewable from both opposed sides of the sign.
It is another object of the present invention to provide a hybrid illuminated indicator sign for visually displaying indicators when the hybrid illuminated indicator sign is electrically powered and for at least a period of time when the hybrid illuminated indicator sign is no longer electrically powered, wherein the indicators of The hybrid illuminated indicator sign are readily changeable.
It is another object of the present invention to provide a hybrid illuminated indicator sign for visually displaying indicators when the hybrid illuminated indicator sign is electrically powered and for at least a period of time when the hybrid illuminated indicator sign is no longer electrically powered, wherein The hybrid illuminated indicator sign is easy to install and replace.
It is another object of the present invention to provide a hybrid illuminated indicator sign for visually displaying indicators when the hybrid illuminated indicator sign is electrically powered and for at least a period of time when the hybrid illuminated indicator sign is no longer electrically powered, wherein the photo-luminescent material glows evenly, or in other words to emits a reasonably constant level of light across its entire surface.
It is yet another object of the present invention to provide a hybrid illuminated indicator sign for visually displaying indicators when the hybrid illuminated indicator sign is electrically powered and for at least a period of time when the hybrid illuminated indicator sign is no longer electrically powered, wherein the hybrid illuminated indicator sign has a slim profile.